scholarly journals Application of microbial risk assessment on a residentially-operated Bio-toilet

2006 ◽  
Vol 4 (4) ◽  
pp. 479-486 ◽  
Author(s):  
Naoko Nakagawa ◽  
Hana Oe ◽  
Masahiro Otaki ◽  
Katsuyoshi Ishizaki
Keyword(s):  
Risk Assessment ◽  
Water Content ◽  
Risk Level ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Infectious Risk ◽  
The Matrix ◽  
Pathogenic Viruses ◽  
Scale Experiment ◽  
Time Required

The Sustainable Sanitation System is a new wastewater treatment system that incorporates a non-flushing toilet (Bio-toilet) that converts excreta into a reusable resource (as fertilizer or humus for organic agriculture) and reduces the pollution load to environments of the rivers, the lakes, and the sea. However, the risk of exposure to pathogens should be considered, because excrement is stored in the Bio-toilet. The aim of the present work is to analyze the health risk of dealing with the matrix (excreta and urine mixed with sawdust) of the Bio-toilet. Therefore, the fate of pathogenic viruses was investigated using coliphages as a virus index, and the modeling of the die-off rate in matrix was introduced. Then the microbial risk assessment was applied to a Bio-toilet that was actually used in a residential house; the infection risks of rotavirus and enterovirus as reference pathogens were calculated. According to the lab-scale experiment using coliphages for investing the die-off rate of viruses in the Bio-toilet, Qβ had a higher die-off, which was greatly influenced by the water content and temperature. On the other hand, T4 showed a lower rate and was independent of water content. Therefore, these two phages' data were used as critical examples, such as viruses having high or low possibilities of remaining in the Bio-toilet during the risk assessment analysis. As the result of the risk assessment, the storage time required for an acceptable infectious risk level has wide variations in both rotavirus and enterovirus cases depending on the phage that was used. These were 0–260 days' and 0–160 days' difference, respectively.

Evaluation of Microbial Risk Assessment Techniques and Applications

2015 ◽  
Vol 3 (0) ◽  
pp. 9781780404141-9781780404141
Author(s):  
J. A. Soller ◽  
A. W. Olivieri ◽  
J. N. S. Eisenberg ◽  
R. Sakajii ◽  
R. Danielson
Keyword(s):  
Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Assessment Techniques

Enteric virus presence in green vegetables and associated irrigation waters in a rural area from Argentina. A quantitative microbial risk assessment

LWT ◽  
2021 ◽  
Vol 144 ◽  
pp. 111201 ◽  
Author(s):  
Prez Verónica Emilse ◽  
Victoria Matías ◽  
Martínez Laura Cecilia ◽  
Giordano Miguel Oscar ◽  
Masachessi Gisela ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Rural Area ◽  
Enteric Virus ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Irrigation Waters

Risk assessment of waterborne protozoa: current status and future trends

Parasitology ◽  
1999 ◽  
Vol 117 (7) ◽  
pp. 205-212 ◽  
Author(s):  
C. J. GIBSON ◽  
C. N. HAAS ◽  
J. B. ROSE
Keyword(s):  
Risk Assessment ◽  
Management Practices ◽  
Assessment Methods ◽  
Detection Methods ◽  
Current Status ◽  
Future Research ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Chemical Risk Assessment ◽  
Low Levels

Throughout the past decade much research has been directed towards identifying the occurrence, epidemiology, and risks associated with waterborne protozoa. While outbreaks are continually documented, sporadic cases of disease associated with exposure to low levels of waterborne protozoa are of increasing concern. Current methodologies may not be sensitive enough to define these low levels of disease. However, risk assessment methods may be utilised to address these low level contamination events. The purpose of this article is to provide an introduction to microbial risk assessment for waterborne protozoa. Risk assessment is a useful tool for evaluating relative risks and can be used for development of policies to decrease risks. Numerous studies have been published on risk assessment methods for pathogenic protozoa including Cryptosporidium and Giardia. One common notion prevails: microbial risk assessment presents interesting complications to the traditional chemical risk assessment paradigm. Single microbial exposures (non-threshold) are capable of causing symptomatic illness unlike traditional chemical exposures, which require a threshold to be reached. Due to the lack of efficient recovery and detection methods for protozoa, we may be underestimating the occurrence, concentration and distribution of these pathogenic micro-organisms. To better utilize the tool of microbial risk assessment for risk management practices, future research should focus in the area of exposure assessment.

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